In South America the sea lay westward of Gondwanaland, marine Trias occurring west of the Andes. In Uruguay, Paraguay and south Brazil continental deposits are remarkably like those of parts of South Africa. The Rio do Rasto Beds comprise varie gated mudstones and sandstones and pass up through aeolian sandstones into the Botucatu Sandstone, which is covered by basaltic lavas that occupy an enormous region in Parana, Santa Catherina, Paraguay, etc. Scaphonyx, from the Rio do Rasto Beds is allied to Erythrosuchus of the Upper Beaufort Beds. The upper groups resemble the Cave Sandstone and Drakenberg Volcanics.
A tillite in eastern Argentina passes up into unfossiliferous beds rather like those of the Falklands, where the thick Lafonian (Permo-Triassic) System covers over one half of the eastern island. Towards the top the facies resembles that cf the Beau fort Beds.
The Appalachian revolution in North America resulted in the uplift of the eastern and southern part of the continent with the concurrent formation of continental deposits. Open sea lay on the Pacific border and extended inland to the site of the Rocky Mountains, where the chief deposits were of fresh-water type.
In the Eastern States disconnected and faulted troughs filled mainly with Middle and Upper Triassic deposits extend from Nova Scotia through Connecticut and New Jersey (Newark System) to South Carolina. Deposits are usually red and every where unconformable to underlying formations. With them are associated sheets (e.g. "palisades" of the Hudson, New Jersey) and dikes of diabase, and basaltic lavas. The Newark System, 20,000 ft. thick, is divided into the Stockton-Norriston, Locka tong and Brunswick Groups. The sediments and their scanty fos
sils (land-plants, fishes and tracks of reptiles) point to deposition under semi-arid conditions.
The finest development of marine Trias is in the Sierras, Cali fornia, Nevada, Idaho and Oregon, where the deposits are usually calcareous and about 4,00o ft. thick. From Vancouver to Queen Charlotte Islands they increase to 13,00o ft., more than nine tenths being volcanic.
The early Triassic sea stretched eastwards possibly to central Wyoming. In middle times it withdrew westward, whilst later it spread from Alaska to northern Mexico. This sea had connec tion with Asia by the northern Pacific, and with "Tethys" by way of the northern shores of Gondwanaland. The deposits can be divided in harmony with the Alpine Trias, California posses sing the best known development of the Upper Trias. The Noric is represented by two zones, in the lower of which coral reefs (Astraeidae) extend from California into Alaska. Almost 25% of the fauna is identical with that of the Mediterranean area.
Throughout the Rocky Mountain region between Canada and western Texas, and in northern New Mexico and Arizona, conti nental Upper Triassic gypsiferous shales and sandstones overlie older eroded formations often of a similar character. They con tain bone conglomerates with amphibia (Stegocephalia), croco dilian types (Mystriosuchus) and dinosaurs. Silicified wood, as in the petrified forest of Arizona (Flagstaff), is common. Plants include cycads, ferns and conifers. Gingkos were represented by Baiera (also in Upper Karroo). The Glossopteris flora, so characteristic of Gondwanaland, is absent. (B. SM.)